Welded assembly and method of making such assembly



June 28, 1966 F. x. BROWN ETAL 3,257,710

WELDED ASSEMBLY AND METHOD OF MAKING SUCH ASSEMBLY Filed Nov. 25,, 1960Fig.4..

INVENTORS Francis X.Brown and Lorin K. Pooh. BY

ATTORNEY United States Patent 3,257,710 WELDED ASSEMBLY AND METHOD OF MGSUCH ASSEMBLY Francis X. Brown, llroomall, and Lorin K. Poole, GlenMills, Pa, assignors to Westinghouse Electric Corpora- 5 tion, EastPittsburgh, Pa., a corporation of Pennsylvania Filed Nov. 25, 1960, Ser.No. 71,777 7 Claims. (Cl. 29-1573) This invention relates to themetals-joining art and has particular relationship to the fabrication oftube-plate or what is called tube-to-tube-sheet assemblies. Suchassemblies include a plate having holes in which a plurality of tubesare secured. Such assemblies are used in heat exchangers and the like;the heat exchange takes place between a hot fluid in the tubes and aheat absorbing fluid enveloping the outsides of the tubes.

In recent years a demand has arisen for a tube-plate assembly in whichthe leakage of the fluid from within the tubes into the heat absorbingfluid is positively prevented. This requires that the tubes be sealedfluid-tight to the plate and that the tube-to-plate joint and the tubesthemselves remain fluid-tight in the use of the assembly.

In accordance with the teachings of the prior art tubeplate assemblieswere made by direct fusion arc-welding with a non-consumable electrodeof the tubes to the rims of the holes in the plate, by arc welding therims of the holes in the plate to the adjacent ends of the tubes with amanual coated electrode, and by fusion arc-welding with a non-consumableelectrode of a filler ring or the equivalent to the joint between therims of the holes and the adjacent ends of the tubes. The assembliesproduced with the first of the above methods were found to have anexcessive number of gas holes and cracks. The second method was found tobe excessively costly; in addition difliculty was experienced inmaintaining a proper bead contour and an excessive number of small leaksappeared in the joints. While the third of the above-described methodsyielded useable assemblies, this method was found to lack adequatepositive reliability for wide industrial use; in addition it was foundthat some of these assemblies were of relatively short life. Severalheat exchangers with tube-plate assemblies made in the practice of thethird method developed leaks in the field.

It is then an object of this invention to provide a method of makingfluid-tight tube-plate assemblies which shall have adequate positivereliability for wide industrial use. It is a specific object of thisinvention to provide a method of making tube-plate assemblies by weldingthe tubes to the rims of holes in the plate in which the welds shall besubstantially free of leaks and cracks and which shall have a relativelylong life in use.

This invention arises from the discovery that the leaks and cracks inthe tube-sheet assemblies made in accordance with the teachings of theprior art arise from the failure to coordinate the metallurgical andmechanical 55 properties of the materials forming the welded joints. An

3,257,710 Patented June 28, 1966 "ice important aspect of this discoveryis that the use of like materials for the tubes and the plate does notachieve this coordination. To achieve the desired metallurgical andmechanical coordination changes must be made in the metallurgy of one orthe other.

It has also been found that the short life which has been experienced ininitially acceptable assemblies is caused by corrosion of the tubes at,and adjacent to, the welds. In the making of the assemblies inaccordance with the third of the above-described methods (and usually inaccordance with the other two) each tube is inserted in itscorresponding hole with the end of the tube extending above the rim ofthe hole and a weld is produced between the rims of the hole and thetube. It has been discovered that during the welding operation aninwardly extending projection is formed at the joint, in effectproducing a Venturi channel. This channel causes the hot fluid whichpasses through the tubes to be turbulent at or near the joints and theturbulence causes the tubes to be corroded at or near the joints and todevelop leaks. This corrosion is particularly severe in the case ofpressurized water frequently encountered in practice which is present inthe tubes at pressure of about 2000 pounds per square inch and at atemperature of about 600 F.

In accordance with this invention the mechanical and metallurgicalproperties of the tubes and plate are coordinated by selecting materialfor the portion of the plate forming the joints which, while differentthan the material of the plate, is weld compatible with the plate. Thetubes or the portions of the tubes forming the joint are also ofdifferent material than the overlay forming the joint.

Weld compatibility between a first material and a second materialdifferent than said first material means that when these materials aremelted or fused while in contact and then permitted to cool there issubstantial mutual solid solubility of each material in the other.Essentially the two materials should have the samemelting-solidification temperature ranges within about 300 Fahrenheitdegrees. The desired solid solubility is not achieved by welding likematerials; one of the materials must be changed.

It is usually not economically feasible to select the plate and thetubes themselves of compatible but different materials although suchselection is within the scope of this invention in its broader aspects.In the practice of this invention in its more specific aspects thecompatibility is achieved by overlaying a base plate with overlays ofmaterials each of which are compatible with the adjacent material ormaterials; the material of the most remote overlay from the base platebeing compatible with the material of the tube. The tube is joined tothis most remote overlay. Thus a completely compatible tube-plateassembly is produced.

The following Table I presents the compositions of base plate, tubes andoverlays which have been produced in the practice of this invention andhave been found to yield highly satisfactory results:

TABLE I Item Type Identifica- Composition Type IdentificationComposition Tube Overlay tion Plate Plate Tube 1 AS'IM A266, KilledCarbon ASTM A210, A" Killed Carbon Steel Stee1.60 to .90 Mn; .06 O; .75to 1,00 Si, A105. Steel. small quantity of powerful deoxidizer such asA1. Overlaid by submerged arc welding with a rimmed steel electrode anda flux containing alloy elements and deoxidizers.

TABLE IC ntinucd Item Type Identifica- Type Identification tion PlateTube Composition Plate Composition Tube Overlay International Nickel Co.Ineonel Alloy.

ASTM A266,

do do ASTM-A2l3 Type 304 Stainless Steel.

ASTM-A266, d0 A105.

Silicon Bronze Admiralty Metal ASTM-B 94.

90 Cu-10 Ni or 80 Cu-Ni or 70 Cu-Ni or 70 Ni-30 Cu. In effect then 30 to00 Cu, 70 to 1st layer MIL-EN61 .15 C; 1.00 Mn; 1.00 Fe;

S .01; Si. 75; Cu .25; A1 1.5; Ti 2 3; miscellaneous elements, .5;remainder Ni N1. plus small percent Co.

2d layer and 3d layer MIL-ENGO C. 15; M111.0();Fe 2.5; S .02; Si 1.5; Niplus small percent cobalt 62 to Al 1.25; Ti 1.5-3; miscellaneouselements .5; remainder Cu. Overlaid by consumable electrode inertgaswelding. (Too deep penetration should be avoided and for this purposeelectrode is oscillated as deposit proceeds.) layers all same. MIL-EN-GAC .10; Mn 22.75; Fe 10; S. 015; Si .35; Cu .5; Ti 2.5-3.5; Cr 14-17;misc. elements .5; Ni|Coremainder but not less than MIL-EN 87 C .10; Mn2.5-3.5; Fe 3.00; S .015; Si .50, Cu .50; Ni 67minimum Co .10; Cb+Ta2.00 3.00 but Ta max. only .3; Ti .75; Cr 18-22. (Same process as for CuNi Item 2.)

First layer. Overlaid by series submerged are weld between electrodes ofASTM-300 and 312 Stainless Stock-adjacent plate.

Second layer. Ovcrlaid by series submerged arc weld between ASTM-308Lelectrodes.

No overlay.

1 Tube joined to second and third layer. 2 Tube joined to second layer.

The data under Overlay in Table I is the composition determined byactual analysis of a specimen of the overlay.

The assemblies listed in Table I are throughout weld compatible.

Thus in the case of item 2 there is substantial mutual solid solubilitybetween the nickel alloy of the first layer and the carbon steel; thereis also substantial mutual solid solubility between the nickel-copper(Monel) alloy of the second layer and the nickel alloy of the firstlayer and also both between the nickel-copper alloy of the second andthird layer and the alloy of the tube.

In the case of the two-or-three-layer overlays the first layer may beeliminated if the penetration of the overlay of the other layers can bemaintained low. This requires excessive care in actual manufacture andfor this reason the two-or-three-layer overlay is preferred.

Table I shows that in producing a tube-plate assembly Where the tubesand plates are both of carbon steel compatibility is achieved with anoverlay of manganesesilicon steel having a powerful deoxidizer. Wherethe tubes are stainless steel type 304 and the base plate carbon steel,a first layer combining 309 and 312 stainless is deposited on the steeland a second layer of 308L stainless is deposited on the first layer.The tubes are welded to the second layer. In this case the balance inthe weld between the chromium and other ferrite forming elements andnickel and other austenite forming elements must be such as to suppresscracking. The joining of tubes of type 304 stainless to a plate of type304 stainless would not yield a non-porous crack-free assembly, amongother reasons because the required relationship of ferrite to autenitein the joint would not be achieved.

To eliminate the turbulence smooth joints without inwardly extendingprojections are produced. This object is achieved by mounting each tubein its corresponding hole with its rim extending below or within the rimof the hole. The tube is initially a slip fit in the hole but the end ofthe tube adjacent the rim in the hole is expanded so that the tubefirmly engages the boundary of the hole to which it is to be welded.

The joining in each case is effected by fusion arc welding with anon-consumable electrode in a shield of inert gas. The welding may becarried out with the apparatus disclosed in Patent 3,064,120 grantedNovember 13,

1962 to Richard P. Ache for Welding Apparatus and assigned toWestinghouse Electric Corporation, or similar apparatus.

Assemblies covered by each item of the Table I have been made as justdescribed and have been successfully qualified both as to weldingprocedure and as to welders (welding operators). In qualifying as toprocedure at least 25 welds corresponding to each item of the table weremade in a test plate. A section of this plate about to /2" below thewelds is then cut. This section is X-rayed to determine if it is free ofporosity. In each test all the welds of each test section were found tobe unusually porosity free. This section is then dyepenetrant tested todetermine if cracks are present. No cracks were found in any of the testsections. Each section is then cut along the diameters of the lines oftubes and the thickness of the welds at their m'nimum thicknesses aremeasured at four points on each of the twenty-five welds. In allmeasurements the welds were at least .9 times the thickness of the tubewall. Macro sections of all twenty-five welds are viewed for flaws.Micro sections of randomly selected welds are viewed for :micro cracksparticularly at the roots of the welded joints. The test welds werefound to be free of flaws and micro cracks. The procedure is qualifiedin this way for each separate gauge of tube.

Welders (welding personnel) are qualified for each eparate gauge oftube. For the first qualification twentyfive welds are made in a plateand a section similar to the above of each plate is X-rayed,dye-penetrant tested, micro viewed, and subjected to thicknessmeasurement as above. For each subsequent qualification l0 welds aremade and tested as above. About twelve welders have been qualified thusfar.

Fourteen satisfactory feed water heaters with tubeplate assemblies inaccordance with this invention have been made thus far in the practiceof this invention. In these assemblies the welds are sound and there areno inwardly extending projections which would produce turbulence of theheated water.

The novel features considered characteristic of this invention aredisclosed in some detail above. Additional understanding of thisinvention, both as to its organization and as to its method of operationand use and additional objects and advantages thereof will be obtained 5from the following description of specific embodiments taken inconnection with the accompanying drawings in which:

FIGURE 1 shows a section of an actual weld made by the prior-artfiller-ring method described above;

FIG. 2 is a view in front elevation of a tube-plate assembly inaccordance with this invention;

FIG. 3 is a view in section taken along line III-III of FIG. 2;

FIG. 4 is a view in section showing a tube and a portion of the platepreparatory to the welding operation; and,

FIG. 5 is a view in section showing a tube and portion of the plate andthe welding electrode as they are related during a welding operation. 1

FIGURE 1 shows a part of a welded assembly made in accordance with theteachings of the prior art including a plate 11 in which tubes 13 and 15are secured by are fusion welding a filler ring at the joint of thetubes and plate. FIG. 1 shows both types of defects in the prior artwelds. The joint has small unwelded holes 17 and 19 and the fusedmaterial 21 projects inwardly producing in effect a Venturi channel. Inaddition the weld has some porosity.

FIGS. 2 and 3 show a tube-plate assembly in accordance with thisinvention. This assembly includes a base plate 31, for example of carbonsteel, on which a plurality of layers 33 and 35 of an overlay aredeposited. Depending on the tube material the overlay may be ofmanganese-silicon steel with a powerful deoxidizer' (for a carbon orsteel tube) or a copper-nickel alloy or a nickelcopper alloy like Monelmetal. The tubes 37 are secured in holes in the overlay by arc welding.

In making the tube-plate assembly shown in FIGS. 2 and 3, the base plateis overlaid and then drilled. The tubes are then inserted in the holes.With reference to FIG. 4 the followin-g Table II shows the tubedimensions, the hole dimensions and the spacing of the tube rim 41 belowthe adjacent rim 43 of the hole for an assembly including tubes of Monelmetal and copper-nickel alloys.

TABLE II Tube Size Tube A Dimen- B Dimen- Material s10n on O.D. WallMonel 17-18 BWG* 0. 055"-0. s" 0. 6300. 650 00-10 CuNi 17-18 BWG 0. oss-o. 005" 0. 630-0. 050" 70-30 01101.. 17-1s BWG 0. 055"-0. 065 0.e30"-0. 650 Monel 15-16 BWG 0. 055"-0. 065" 0. 6300. 650" 90-10 OuNL.15-16 BWG" 0. 055"-0. 065 0. saw-0. 050" 70-30 CuNL- 15-16 BWG 0.055"-0.005" 0. 030"-0. 650

*Birmingham Wire Gauge.

The tube 45 should be a slip fit in the hole 47. Typically, a hole ismaintained between .631 and .633 inch and the outside diameter of a tubebetween .620 and .630. Preferably the tube rim. 41 should be square andnot tapered to provide adequate thickness for the fusion weld.

FIG. 5 and the associated following Table III show the relationshipbetween the elcetrode 49 and each tube 45 in the plate 47 and thewelding parameters during the welding operation:

0 The plate is placed horizontally on a table and the electrode 49 isheld at an angle of about to the vertical and at a trailing angle ofabout 5 In detail a typical operation is carried out as follows:

5 OPERATIONS (1) Preparation for Welding (2) Tube Welding Procedure (3)Post Weld Inspection 10 (1) Preparation for welding (1) Prior towelding, both the plate and the tubes are properly prepared.

(2) Tubes are rolled to a plastic deformation of 2% to 4% by retractiverolling the full depth of the plate less one-eighth-of-an-inch. Aminimum amount of water soluble Lube-A-Tube lubricant is used.

(3) After rolling, the tube ends are cut off below the plate. For depthsee Table II. The cut off tool is electrically driven to avoidcontaminating the tube end. No lubricant is used for this operation.

(4) After cut-01f the inside of the tube end is debur-red using a handreamer.

(5) The plate is thoroughly cleaned of all dirt, grease, oil, and chipsafter the tube ends have been prepared for welding and the plate is thencovered with heavy cardboard to insure cleanliness. Thorough cleaning ishighly important.

(2) Tube welding procedure (1) The unit is placed in the verticalposition with the plate horizontal for welding.

(2) No preheat is required, except that the plate temperature shall notfall below 70 F.

(3) Immediately prior to positioning of the welding torch, the tube tobe welded is snugged against the tube hole using a tapered drift.

(4) Welding is done with a machine having a high frequency are startingattachment and an arc tapering attachment. The welding is done usingD.C. straight polarity.

(5) Interpass temperature does not exceed 150 F. as measured by acalibrated contact pyrometer.

(6) Welding current, voltage, gas flow, and rotation time are asspecified in Table II for the tube gauge (Birmingham Wire Gauge) andmaterial being welded.

(7) Before each shift two welds are made on a test block to determinethat the equipment is functioning properly.

(3) Post weld inspection (1) After the welding has been completed theWelds are cleaned of all scale and oxide and inspected visually with a5X lens for voids, cracks, non-fusion etc. Defects may be repaired.Small defects may be rewelded. In the case of large defects filler maybe added.

(2) After all repairs have been made the completed plate is subjected toa penetrant examination.

The above-described method has resulted in highly satisfactoryporosity-free crack-free long-life assemblies. While preferredembodiments of this invention have been disclosed herein manymodifications thereof are feasible.

TABLE III Tube Size Gas Tube Material Flow, Current Rotation DimensionDimension c.f.h. Amperes Speed 0 D O.D. Wall Argon 8 17-18 BWG 10 85-9045 Sec./Rev. 0. 030-. 040" 0.320 17-18 BWG- 10 85-90 45 See/Rev... 0.030-. 040 0. 320 17-18 BWG- 10 85-90 45 See/Rev.-. 0. 030-. 040 0.32015-16 BW Gr 10 85-90 45 Sec./Rev 0. 030-. 040" 0. 320" 5 15-16 13W6%.... 10 85-90 45 See/Rem 0. 030-. 040" 0. 320 -30 On NL..- 3 15-16 BWG10 -90 45 See/Rev-.. 0. 030-. 040" 0. 320

This invention then is not to be restricted except insofar as isnecessitated by the spirit of the prior art.

We claim as our invention:

1. The method of producing a fluid-tight tube-plate assembly with aplate and a plurality of tubes which comprises overlaying said plate byweld depositing an overlay of a diiferent material than the material ofsaid plate and of an alloy content having weld compatibility with thealloy content of said tubes and of said plate, said overlay extendingsubstantially throughout the area of said plate so as to suppress theconcentration of heatof said weld depositing in the region where saidoverlay and plate are contiguous, providing in said overlaid plate holeshaving dimensions corresponding to the dimensions of said tubes,inserting a tube in each of said holes, and Welding each said tube andsaid plate at the joint between each said tube and said plate.

2. The method of producing a fluid-tight tube-plate assembly with aplate and a plurality of tubes, said plate being composed of at leasttwo laminations metallurgically joined throughout, one of saidlaminations being of a different composition than said other laminationand having an alloy content having weld compatibility with the alloycontent of said tubes, the said method comprising providing, in saidplate, holes having dimensions corresponding to the dimensions of saidtubes, inserting a tube in each of said holes with said last-named tubeforming a joint with the boundary, in said one lamination of said alloycontent, of the hole in which said last-named tube is inserted, andwelding said last-named tube to said plate with a peripheral weld aroundsaid joint.

3. The method of producing a fluid-tight tube-plate assembly with aplate and a plurality of tubes which comprises overlaying said plate byweld depositing an overlay of a different material than the material ofsaid plate and of an alloy content having weld compatibility with thealloy content of said tubes and of said plate, said overlay beingmetallurgically joined to said plate, providing in said overlaid plateholes having dimensions corresponding to the dimensions of said tubes,inserting a tube into each of said holes with the rim of said lastnamedtube extending a predetermined first distance below the rim of saidlast-named hole but within said overlay, and welding each of said tubesto said plate with a peripheral weld metallurgically joining said rim ofsaid last-named tube to said overlay, said weld being produced with anon-consumable electrode whose tip remains spaced throughout the weldinga predetermined second distance from said last-named hole, said firstand second distances being such, and the said welding being carried outin such a way as, to suppress the formation during the welding, ofprojections extending inwardly towards the axis of said tube at eachjoint of said tube and overlay.

4. The method of producing a fluid-tight tube-plate assembly with aplate and a plurality of tubes, said tubes being composed of a firststainless steel, the said method comprising overlaying said plate byWeld depositing an overlay of a second stainless steel different fromsaid plate and tubes and of an alloy content having weld compatibilitywith the alloy content of said tubes and of said plate, said first andsecond steels when welded producing a balance of austenite and ferritein the weld so as to suppress cracks, said overlay being metallurgicallyjoined to said plate and extending over an extensive area of said plate,providing in said overlaid plate holes having dimensioons correspondingto the dimensions of said tubes, inserting a tube into each of saidholes with the rim of said last-named tube extending a predeterminedfirst distance below the rim of said last-named hole but within saidoverlay, and fusion welding each said tube to said overlay with aperipheral weld metallurgically joining said rim of said last-named tubeto said overlay,

said weld being produced with a non-consumable electrode whose tipremains spaced throughout the Welding a predetermined second distancefrom said last-named hole, said first and second distances being such,and the said welding being carried out in such a way as, to suppress theformation during the Welding, of projections extending inwardly towardsthe axis of said tube at each joint of said tube and overlay.

5. The method of producing a fluid-tight tube-plate assembly with aplate and a plurality of tubes, at least a part of said plate having analloy content having weld compatibility with the alloy content of saidtubes, the said method comprising providing in said plate holes havingdimensions corresponding to the dimensions of said tubes, inserting atube in each of said holes with the rim of said last-named tube apredetermined first distance below the rim of said last-named hole, saidrims being in said part of said plate, and Welding said last-named tubeto said plate with a peripheral weld metallurgically joining said rim ofsaid last-named hole and said rim of said last-named tube, said weldbeing produced with a non-consumable electrode whose tip remains spacedthroughout the welding a predetermined second distance from saidlast-named hole, said first and second distances being such, and saidwelding being carried out in such a way as, to suppress the formation,during the welding, of projections extending inwardly towards the axisof said tube at said joint of said tube and plate.

6. The method of producing a fluid-tight tube-plate assembly with aplate and a plurality of tubes, at least a part of said plate having analloy content having weld compatibility with the alloy content of saidtubes, the said method comprising providing in said plate holes havingdimensions corresponding to the dimensions of said tubes, the dimensionsof each said hole being so related to the dimensions of thecorresponding tube that said tube is a slip fit in said last-named hole,inserting a tube in each of said holes with the rim of said lastnamedtube a predetermined first distance below the rim of said last-namedhole, said rims being in said part of said plate, expanding at least theportion of said lastnamed tube adjacent the rim thereof so that saidportion tightly engages the adjacent portion of said hole, and weldingsaid last-named tube to said plate with a peripheral weldmetallurgically joining said rim of said last-named hole and said rim ofsaid last-named tube, said weld being produced with a non-consumableelectrode whose tip remains spaced throughout the welding apredetermined second distance from said last-named hole, said first andsecond distances being such, and said welding being carried out in sucha way as, to suppress the formation, during the welding, of projectionsextending inwardly towards the axis of said tube at said joint of saidtube and plate.

7. The method of producing a fluid-tight tube-plate assembly with aplate and a plurality of tubes, said plate being composed of at leasttwo laminations metallurgically joined throughout, one of saidlaminations being of a different composition than said other laminationand having an alloy content having weld compatibility with the alloycontent of said tubes, the said method comprising providing, in saidplate, holes having dimensions corresponding to the dimensions of saidtubes, inserting a tube in each of said holes with said last-named tubeforming a joint with the boundary, in said one lamination of said alloycontent, of the hole in which said last-named tube is inserted, the rimof said last-named tube being in said one lamination of said alloycontent but below by a predetermined first distance the outer rim ofsaid last-named hole, and welding said last-named tube to said platewith a peripheral weld around said joint, said weld being produced witha non-consumable electrode whose tip remains spaced throughout thewelding a predetermined second distance from said last-named hole, saidfirst and second distances being such, and the said welding beingcarried out in such a Way as, to suppress the formation during thewelding of projections extending inwardly towards the axis of said tubeat said joint.

References Cited by the Examiner UNITED STATES PATENTS Mautsch 165134Carlson et a1. 29-196.1 Morris et a1 29157.4

Gier 29157.3 Carpenter 29-492 X Orr et a1. 257236 Ryder 257-235 Worn eta1. 29-157.5

Hawthorne 285286 X Chapman 285-286 X Pepper et a1. 29157.3 Taga 165-173Patriarca et a1. 29483 X Davies et a1 165134 Carpenter 29157.4 X

ROBERT A. OLEARY, Primary Examiner.

CHARLES SUKALO, Examiner.

T. W. STREULE, Assistant Examiner.

1. THE METHOD OF PRODUCING A FLUID-TIGHT TUBE-PLATE ASSEMBLY WITH APLATE AND A PLURALITY OF TUBES WHICH COMPRISES OVERLAYING SAID PLATE BYWELD DEPOSITING AN OVERLAY OF A DIFFERENT MATERIAL THAN THE MATERIAL OFSAID PLATE AND OF AN ALLOY CONTENT HAVING WELD COMPATIBILITY WITH THEALLOY CONTENT OF SAID TUBES AND OF SAID PLATE, SAID OVERLAY EXTENDINGSUBSTANTIALLY THROUGHOUT THE AREA OF SAID PLATE SO AS TO SUPPRESS THECONCENTRATION OF HEAT OF SAID WELD DEPOSITING IN THE REGION WHERE SAIDOVERLAY AND PLATE ARE CONTIGUOUS, PROVIDING IN SAID OVERLAID PLATE HOLESHAVING DIMENSIONS CORRESPONDING TO THE DIMENSIONS OF SAIDTUBES,INSERTING A TUBE IN EACH OF SAID HOLES, AND WELDING EACH SAID TUBEAND SAID PLATE AT THE JOINT BETWEEN EACH SAID TUBE AND SAID PLATE.